Area Forecast Discussion
Issued by NWS Central Illinois

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FXUS63 KILX 250126
AFDILX

Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
826 PM CDT Sun Aug 24 2014

.UPDATE...
ISSUED AT 822 PM CDT SUN AUG 24 2014

Cold front over far western Iowa early this evening will be making
a slow push to the east over the next couple of days with an
increasing chance for showers and thunderstorms to our west and
north, and eventually into parts of central Illinois late tomorrow
night into Tuesday. Dew points once again this afternoon were in
the 75 to 80 degree range with heat index values as high as 111
degrees in Springfield at 300 pm. Another very warm/sultry night
across the region with light winds and a mostly clear sky, which
will lead to some patchy fog again towards morning. Most areas will
drop off only into the low to mid 70s overnight.

Storms are expected to expand in coverage well up to our northwest
late tonight and drift southeast towards the lower Great Lakes
Monday morning before dissipating as they encounter the upper level
ridge. With abundant sunshine expected again on Monday, look for
afternoon temps to climb into the low to mid 90s and heat index values
104 to 111 degrees. Models indicating the upper level ridge will be
very slow to break down thru Monday evening with most of the rain
chances remaining to our north. Finally, by later Tuesday, a series
of shortwaves riding the top of the ridge will start to deamplify the
pattern over the lower 48 and shift a frontal boundary into our area
bringing periodic chances for showers and thunderstorms to the central
Illinois along with a gradual cooling trend as we head thru the second
half of the week.

Current zone forecast product in good shape this evening so will
not be sending out any updated forecast at this time.

&&

.SHORT TERM...(This evening through Monday)
ISSUED AT 303 PM CDT SUN AUG 24 2014

Quiet weather is expected through the short-term, as upper-level
ridging dominates the weather.  Any convection that occurs tonight
will develop well to the northwest across central/western Iowa along a
slow-moving cold front.  This activity will lift northeastward into
Wisconsin on Monday, remaining well north of the KILX CWA.
Potential outflow boundary from this convection will stay to the
north as well, as synoptic subsidence keeps skies mostly clear.  As
a result, have removed slight chance PoPs from the far north Monday
afternoon.  Main story will be the heat, as high temperatures on
Monday will be a degree or two warmer than today.  Afternoon highs
on will climb into the lower to middle 90s, with peak heat index
values reaching 105 degrees or higher across the whole CWA.

&&

.LONG TERM...(Monday night through Sunday)
ISSUED AT 303 PM CDT SUN AUG 24 2014

First concern this forecast period is the heat that will be a
continuance from the short term into Tuesday. Also, with the models
slowing the front from coming into the area, have decided to expand
the advisory to include the rest of the CWA and to extend the
advisory into Tuesday afternoon. The front will get closer to the
area Tuesday and this could bring some pcpn into the northern parts
of the CWA during the day. This pcpn and cloud cover could keep the
northern three counties from getting heat advisory criteria, but
will let the day shift cancel there early if need be. So, advisory
has been expanded in area and extended in time into Tuesday.

The cold front will advect into the area Tue night and Wed and this
will lead to a chance of thunderstorms progressing south and
covering the whole CWA by Wednesday. Unfortunately, this front is
forecast to remain over or near the CWA through the week and into
the weekend. So, the rest of the extended forecast has a chance of
thunderstorms for most of the CWA through Sunday. The positive side
to this is that with pcpn and clouds over the area through the
period, the temperatures will be cooler than this past week. It
appears afternoon high temps will be around normal, which is in the
middle 80s. Lows will drop back down into the 60s as well.

MOS guidance looks to be on the warm side for high temps, given the
pcpn and clouds forecasted to be in the area through the period. Low
temps look to be ok.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 600 PM CDT SUN AUG 24 2014

VFR conditions will continue thru the evening with another chance
for patchy fog bringing MVFR or local IFR vsbys in the 09z-13z time
frame. Quiet weather expected this forecast period with high pressure
firmly establised aloft and expected to hold over our area thru Monday
evening. Forecast soundings showing any fog that develops early Monday
morning should quickly lift with mainly few-sct cumulus at around
4000 feet developing by late morning or early afternoon. Surface winds
tonight will light southeasterly at 5 kts or less and then become
south to southwest on Monday at around 10 kts.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
EXCESSIVE HEAT WARNING until 7 PM CDT Tuesday FOR ILZ042-047>054-
056-061>063-066>068-071>073.

HEAT ADVISORY until 7 PM CDT Tuesday FOR ILZ036-040-041.

HEAT ADVISORY from Noon Monday to 7 PM CDT Tuesday FOR
ILZ027>031-037-038-043>046-055-057.

&&

$$

UPDATE...SMITH
SHORT TERM...BARNES
LONG TERM...AUTEN
AVIATION...SMITH



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